Miso

Ingredients

• 1 kgdried soybeans, preferably a Japanese variety
• 1 kgrice koji (Aspergillus oryzae grown on steamed rice), fresh or dried
• 440 gsea salt, plus 30 g for the seal
• 60 gmature unpasteurised miso, as a starter (tanemiso)
• cooled soybean cooking liquid, as needed

Equipment

• 1glazed ceramic crock or food-grade tub of 5 litres, scalded
• 2.5 kgof clean weights (a sealed bag of salt is ideal)
• greaseproof paper and cloth for covering

Directions

1. Wash the soybeans until the water runs clear and soak them in three times their volume of cold water for 18 hours. They should triple in weight and split cleanly when squeezed.
2. Boil the drained beans in fresh water for 3–4 hours, skimming the foam, or pressure cook 40 minutes, until a bean crushes to paste between thumb and little finger with no resistance. Reserve the cooking liquid.
3. Drain and mash the beans while hot, by hand in a bag or through a mouli, leaving some texture. Cool to below 40°C (105°F) or the koji enzymes will be killed.
4. Break up the koji with your fingers and rub it thoroughly with the 440 g of salt so every grain is coated. This salt level, about 12 percent of the finished paste, is the safety of the ferment.
5. Mix the salted koji into the mashed beans with the starter miso, adding cooled cooking liquid a little at a time until the mass has the texture of stiff mashed potato, damp but not wet.
6. Roll the mixture into balls the size of a fist and throw them hard, one at a time, into the bottom of the crock. Press each layer down flat with your knuckles. Air pockets are where mould grows.
7. Level the surface, wipe the sides of the crock spotless, and cover the miso with a thin even layer of the reserved 30 g of salt.
8. Lay greaseproof paper directly on the surface, set a plate or wooden lid on top, add the 2.5 kg weight, cover with cloth and tie it down. Keep at 15–25°C (60–75°F) out of direct sun.
9. After 2–3 months a dark liquid, tamari, rises around the weight; either stir it back or draw it off. In midsummer turn the whole batch over (tenchi-gaeshi), scraping the sides, then repack and re-weight.
10. Ferment 6 months for a young, sweet miso and 12–18 months for a dark, savoury one. It is ready when it smells nutty and sweet with no raw bean note; refrigerate to stop it darkening further.

Technique

• The koji ratio decides the style. More rice koji and less salt with a short warm ferment gives sweet white shiro miso; less koji, 12–13 percent salt and up to three years gives dark red aka miso. Hatcho miso from Aichi uses soybean koji only and no rice at all.
• White surface mould (Kahm yeast) or a patch of blue is normal at the edges: scrape it off, wipe the rim with spirit and re-cover. A salt level below about 5.5 percent is the point at which a long ferment stops being safe.
• The weight is not decorative. It presses out air and keeps the paste under its own liquid, which is what excludes spoilage organisms.
• Never boil miso. Heat above about 80°C (175°F) kills the aroma and, in unpasteurised miso, the live cultures.

Substitutions

• No fresh rice koji: dried koji works identically, but rehydrate it in 200 ml of warm water for 30 minutes before salting.
• Barley koji in place of rice gives mugi miso, the rustic style of Kyushu, with a rougher, grainier texture.
• Chickpeas make a workable soy-free miso, though it ferments faster and stays paler.

Variations

• Shiro miso from Kyoto, only 5–6 percent salt and fermented weeks rather than years, used for saikyo-yaki and sweet dressings.
• Aka miso and Hatcho miso from Nagoya, dark, tannic, and aged in cedar vats under a pyramid of river stones.
• Awase miso, a house blend of red and white, which is what most Japanese families keep in the fridge.

History

Developed from Chinese fermented pastes by the Nara period; regional styles diverged with climate, giving Kyoto sweet white and Nagoya’s dark hatcho.

Frequently asked questions

What is Miso?

Miso is a fermented & pickled from Japan: salted soybean paste fermented with koji, from sweet white to dark red. Developed from Chinese fermented pastes by the Nara period; regional styles diverged with climate, giving Kyoto sweet white and Nagoya’s dark hatcho.

How long does Miso take to make?

Miso takes 1 hr plus overnight soaking of preparation and 6 to 18 months fermentation of cooking. The recipe makes about 2.6 kg of miso. It is rated hard to make.

What can I substitute in Miso?

Yes, within limits. No fresh rice koji: dried koji works identically, but rehydrate it in 200 ml of warm water for 30 minutes before salting. Barley koji in place of rice gives mugi miso, the rustic style of Kyushu, with a rougher, grainier texture. Chickpeas make a workable soy-free miso, though it ferments faster and stays paler.

What is the most important thing to get right in Miso?

After 2–3 months a dark liquid, tamari, rises around the weight; either stir it back or draw it off. In midsummer turn the whole batch over (tenchi-gaeshi), scraping the sides, then repack and re-weight.